Air compressors commonly have difficulty in producing adequate air flow under peak demands and also may have a pulsating air output. For example, a typical air compressor design has a piston which reciprocates in a cylinder alternately between an intake stroke and a compression stroke. Compressed air is available from the compressor only during the compression stroke. In order to smooth out the air flow, to provide an air reserve during peak demand periods and to allow the compressor motor to be idled down or stopped when there is either a low demand or no demand for compressed air, the compressor is commonly connected to a reservoir tank. The tank will have a volume equal to the compressor output over a period of time. A switch turns the compressor motor on when the tank pressure drops to a preset low level and off when the tank pressure reaches a preset high level. The air pressure in the tank dampens pulsations from the compressor. A tool or other air consumer draws compressed air from the tank. During use of a compressed air tank, it is common for water or other liquids to condense from the air in the tank as a consequence of the pressures and temperatures. These liquids may contain acid or other corrosive substances. The source of the acid or corrosive substance may include, but is not limited to, atmospheric gases or contaminants, lubricating oil or its by-products, or other compressor materials released into the air receiver as a result of wear. Typically, a drain plug or drain valve is installed at a low point in the bottom of the air tank. Periodically, the plug is removed or the drain valve is opened to allow any accumulated condensate to drain from the tank.
When condensate is allowed to remain in an air tank, the tank can corrode and eventually fail. Tank corrosion may be increased by a low Ph in the accumulated condensate, i.e., acidic water, or by electrolysis if different metals are present in the tank, such as at a weld.